Hubbardiastrobus cunninghamioides gen. et sp. nov., Evidence for a Lower Cretaceous Diversification of Cunninghamioid Cupressaceae

Abstract

The occurrence of six ovulate cones and six leafy branching systems, two of which show attachment of the ovulate cone, reveals a new cunninghamioid fossil conifer from the Cretaceous Apple Bay locality of Vancouver Island, Canada. This anatomically preserved plant expands our understanding of basal Cupressaceae in the fossil record. Methodology. Specimens were studied from anatomical sections prepared by the classic cellulose acetate peel technique. Pivotal results. Vegetative shoots have helically arranged Cunninghamia-like leaves with a single vascular bundle and one to three resin canals. Ovulate cones consist of numerous helically arranged bract/scale complexes with a large bract and a small ovuliferous scale with three separate tips. There are three inverted seeds/ ovules attached adaxially, immediately proximal to the free scale tips. Conclusions. This discovery reveals the presence of a new genus and species of basal Cupressaceae, Hubbardiastrobus cunninghamioides, in the Early Cretaceous (Valanginian; ∼136 Ma) of the Northern Hemisphere. These data expand the species richness of fossil Cupressaceae and further document the Cretaceous evolutionary radiation of subfamily Cunninghamioideae.

The Early Cretaceous Apple Bay flora of Vancouver Island: a hotspot of fossil bryophyte diversity

“…The flora includes lycophytes, equisetophytes, several fern families (Smith et al 2003;Hernandez-Castillo et al 2006;Little et al 2006aLittle et al , 2006bRothwell and Stockey 2006;Stockey et al 2006;Vavrek et al 2006;Rothwell et al 2014), as well as numerous gymnosperms (Stockey and Wiebe 2008;Stockey and Rothwell 2009;Klymiuk and Stockey 2012;Rothwell and Stockey 2013;Rothwell et al 2014;Atkinson et al 2014aAtkinson et al , 2014bRay et al 2014), fungi (Smith et al 2004;Bronson et al 2013), a lichen (Matsunaga et al 2013), and numerous bryophytes ).…”

Stockeystrobusgen. nov. (Cupressaceae), and the evolutionary diversification of sequoioid conifer seed cones

“…As is common for species of Cupressaceae, the bract-scale complex vasculature of S. interdigitata diverges from the cone stele as a single bundle ( Fig. 2C; Lemoine-Sebastian 1968, 1969Owens and Molder 1975) that divides distally (Table 1; Lemoine-Sebastian 1968, 1969Ohsawa 1994;Rothwell et al 2011;Atkinson et al 2014aAtkinson et al , 2014b. As interpreted by Lemoine-Sebastian, the adaxial bundles would represent the ovuliferous scale, while the abaxial bundle represents the bract trace (Lemoine-Sebastian 1968, 1969.…”

“…Ana-tomically preserved fossil seed cones serve as important intermediates for a transformational series from Voltziaceae to Cupressaceae (Rothwell et al 2011). The largest number of such fossils either are assignable to, or have a great similarity to seed cones of the subfamily Cunninghamioideae (e.g., Rothwell et al 2011;Atkinson et al 2014aAtkinson et al , 2014b.…”

A new species ofAthrotaxites(Athrotaxoideae, Cupressaceae) from the Upper Cretaceous Raritan Formation, New Jersey, USA

“…The absence of an adaxial free tip of the ovuliferous scale (i.e., ligule-like scale, sensu Nishida et al 1992) represents the main morphological difference between A. stockeyi and Parataiwania. The presence of one or several free scale tips also represents a clear difference among our specimens and other basal cupressaceous fossil genera (see Table 1 in Atkinson et al 2014a), such as Hughmemillerites (Rothwell et al 2011;Atkinson et al 2014a), Hubbardiostrobus (Atkinson et al 2014b), and most species in Cunninghamiostrobus (e.g., Miller and Crabtree 1989). Cunninghamiostrobus yubariensis, from the Late Cretaceous of Japan, is also characterized by the lack of free scale tips on the adaxial side of the OCs (Ohana and Kimura 1995).…”